In this report, Gluconobacter strains were screened for coenzyme Q10 (CoQ10) production. A thermotolerant strain, Gluconobacter japonicus FM10, was eventually employed for CoQ10 production optimization. To do so, a two-step optimization strategy was used. The first step focused on biomass increase and the second step focused on increase in CoQ10 production. Factors including temperature, pH, carbon, and nitrogen sources were optimized at the first step, and temperature, pH, and aeration were optimized at the second step. The batch culture fermentation was used with the optimized factors of the first phase (30 °C, pH 6.5, D-sorbitol, and yeast extract-peptone as the carbon and nitrogen sources). After 18 h, the temperature, pH, and aeration were shifted to the optimized values of the second step (36 °C, pH 7, and no aeration). By this strategy, the dry cell mass (17.1 g/L) and CoQ10 (23.2 mg/L) were obtained after 20 h, which the latter was 2.3 times higher than that of the first step of optimization. Among the conditions tested, carbon source was the most important factor on the cell growth at the first step while no aeration was the key factor for CoQ10 production in the second step of optimization.
- MeSH
- dusík metabolismus MeSH
- fermentace MeSH
- Gluconobacter chemie genetika růst a vývoj metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média metabolismus MeSH
- ubichinon analogy a deriváty biosyntéza MeSH
- uhlík metabolismus MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
Biotransformation of glycerol to 1,3-dihydroxyacetone was carried out in an isothermal isochoric batch reactor with Gluconobacter oxydans immobilized in poly(vinyl alcohol) gel capsules. The reaction course was described with a three-step kinetic model. Two reaction schemes were proposed and compared with 8 kinetic experiments at 25 °C. The experimental dependences of glycerol and dihydroxyacetone concentrations on reaction time were simulated very well by the autocatalytic model. The effects of reaction temperature and initial concentrations of yeast extract and glycerol were studied. Temperature 25-30 °C, initial yeast extract concentration 2-4 g l-1 and initial glycerol concentration 20-50 g l-1 were found as optimal. The determined rate constants can be used to advantage for industrial production of dihydroxyacetone from glycerol.
